From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 89C18477E33; Tue, 16 Jun 2026 18:26:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781634376; cv=none; b=MQiRUrgvN/S83SwKRlpPJRHhbvj16B00ItQBJMTryz9p0u11Fe95Bmd4SgEsnpZ0oE57JOKII/St1TSvP8JnbLbCWQ5eFN9Evmew8NNRRrSZqDQZRhdS1E9L/RhtV+9M5SJuIjRxLy+lMZJhkTtatQG4ZFAwuXitcdQnEbhbC0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781634376; c=relaxed/simple; bh=AL4vWMi92ZDakokQTDL2jpOdJL0JuF3eSPqiMeRmMmY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pQ1Yt4gFpitEABt8YvVOt7vhkE8KO6+nCJ0YxgqHYJkc68Z/hBrzua3wkwmxq5axpwVBOmCzwJaEzOJliYS3lax0j9VLB/6f2IniHreRwUdm+ZxoQ2F9VTyobDsnjeM0URm+UjAXNrAzKGz2f7BibYIFD+c3pWYbUUwmQy6PSG4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yDS547TP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yDS547TP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8347E1F000E9; Tue, 16 Jun 2026 18:26:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781634375; bh=75M0BV8WtNiYCQQulGvQpyNpTpfQc1aKhFOWxVvxivs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=yDS547TPSUfY0JsCC6lY2vdWQdEG2BBbh9+0EMZ13iMscDNkjH4033ViLytxC5S0l Z+0Vlr80/slYZl/zSdTOP3lAhU2VwiPx7QPv4rZZVOqZBEpH//lZPAVesWmqzuNRIh gUu5wovGHXwud9H//PRE7acnrByzDit+Kv/6kaDo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, syzbot+6e4cb1cac5efc96ea0ca@syzkaller.appspotmail.com, Yongpeng Yang , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 5.15 252/411] f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() Date: Tue, 16 Jun 2026 20:28:10 +0530 Message-ID: <20260616145114.387704917@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145100.376842714@linuxfoundation.org> References: <20260616145100.376842714@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yongpeng Yang [ Upstream commit 2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53 ] The xfstests case "generic/107" and syzbot have both reported a NULL pointer dereference. The concurrent scenario that triggers the panic is as follows: F2FS_WB_CP_DATA write callback umount - f2fs_write_checkpoint - f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA) - blk_mq_end_request - bio_endio - f2fs_write_end_io : dec_page_count(sbi, F2FS_WB_CP_DATA) : wake_up(&sbi->cp_wait) - kill_f2fs_super - kill_block_super - f2fs_put_super : iput(sbi->node_inode) : sbi->node_inode = NULL : f2fs_in_warm_node_list - is_node_folio // sbi->node_inode is NULL and panic The root cause is that f2fs_put_super() calls iput(sbi->node_inode) and sets sbi->node_inode to NULL after sbi->nr_pages[F2FS_WB_CP_DATA] is decremented to zero. As a result, f2fs_in_warm_node_list() may dereference a NULL node_inode when checking whether a folio belongs to the node inode, leading to a panic. This patch fixes the issue by calling f2fs_in_warm_node_list() before decrementing sbi->nr_pages[F2FS_WB_CP_DATA], thus preventing the use-after-free condition. Cc: stable@kernel.org Fixes: 50fa53eccf9f ("f2fs: fix to avoid broken of dnode block list") Reported-by: syzbot+6e4cb1cac5efc96ea0ca@syzkaller.appspotmail.com Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim [ folio => page ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/data.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -339,6 +339,8 @@ static void f2fs_write_end_io(struct bio f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) && page->index != nid_of_node(page)); + if (f2fs_in_warm_node_list(sbi, page)) + f2fs_del_fsync_node_entry(sbi, page); dec_page_count(sbi, type); @@ -350,8 +352,6 @@ static void f2fs_write_end_io(struct bio wq_has_sleeper(&sbi->cp_wait)) wake_up(&sbi->cp_wait); - if (f2fs_in_warm_node_list(sbi, page)) - f2fs_del_fsync_node_entry(sbi, page); clear_page_private_gcing(page); end_page_writeback(page); }